Resistance device for electric-current controllers.



No. 815,317. C I 'PATENTED MAR.13.1906. L; BRADLEY.

RESISTANCE DEVICE FOR ELECTRIC CURRENT CONTROLLERS. inuonmx mm JULY 9.1602.

the action of the..elec tric current UNITED STATES PATENT- OFFICE.

LYNDE BRADLEY, OF MlLlVAUKEE, WISCONSIN, ASSIGNOR .OF ONE-HALF TO STANTON ALLEN, ()F MILWAUKEE, WISCONSIN.

RESISTANCE DEVICE FOR ELECTRIC-CURRENT CONTROLLERS.

Specification of Letters Patent.

Application filed uly 28, 1902- Serial No. 117,286.

Patented March 13. 1906.

T n all whom it may concern:

Be it known that I, LYNDE BRADLEY, residing at ll lilwaukce, in the county of iiwaukec and State of Wisconsin, have invented a new and useful Improvementin Resistunce Devices forElectric-CurrentControllers, of which the following is a description, reference being bad to the accompanying drawin s, which are a part of this specification.

i'iy invention has relation to improvements in resistance devices for electric-current controllers. Y

lleretofore in the use of carbon disks as a resistance medium in electric-controlling devices wherein theorising containing the disks is not substantially air-tight entireh satisfactory results have not been obtained, by reason of the fact that such material quickly deteriorates with use, owing to said materialcorroding by the action of air thereon, to which it is exposed.

It is thereforethe primary object of my in' vention'to provide a. construction for rendering a variable-resistance r'nedium in the form of carbonaceous plates substantially proofsgainst the action thereon by inci os nggard plates,, ontamerpf sue l q l and eonsequ enhdisintegrati thereofat the temperature to which they are subjectedhy ,assmg therethro ugh, and said construction a' '80 providing for the. retention of the carbon-dioxid gas, which being heavier! than the air'will assist in preventing the air from gaming access to the plates and deleteriously effecting said plates.

' Afurther objectrcsides in the provision of an improved construction whereby the-carbon disks are so protected as not only to be ren dered substantiallyproof against the entrance of air thereto, but is also rendered substantially proof against thc'admission; of dust thereto.

\lVith theabove in view the inventione usists of the devices and parts, or their 'et ui\ nlents, as hereinafter set forth..

In the accompanying drawings, Figure I a vertical sectional"view.of a, r esisl niit-;o medium constructed incler lmlqtgwah ilny maraiimii r. em i0 midi.

igpq yfg 't net-gassesor air fronrthggp ates the oxidation (if said-plates 'j di another wire being in clcetriezil 0 94211151331 5 1 1: I

per portion of atmodilied form of resistance 1219(111111), and Fig. 3 is a similar view of the upper portion of still another modified form.

Referring to the drawings, the numeralA indieates'a tube-or container, usually of metal. At the end of this tube is a cupshape socket 5,-conn'iosed of some suitable insulating material, preferably asbestos. Resting upon the bottom of this socket is a block 6, )rcferably of metal. The cupshaped socket 5 isitself seated in a largeouter cup-shaped socket 7 preferably of metal. This socket 7 has its upwardly-cxtending an- .nular flange interior-1y threaded to engage exterior'threads at the lower end ofthetube 4. Within the tube 4, and closely hugging the inner wall of said tube, is an interior tube 8. This tube is eomposedof a suitable insulatingmaterial,preferablyasbest,os,(alth0u"h any other desirable material may-be used and serves 'to preventthe electric current which' flows through the. resistance medium from passing onto theontritubc 4. The lower end of the insulating-tube 8 extends into the cup-shaped socket Band surrounds the; block 6. The said block 6. is provided "with a depending 'bindingtpost 9, which passes through"arropenin :-l0 in thecupshaped iilncr -soltct'fi;"and alsotlirough an insulating-bushing 11, the said bushing 11 fitting in an opening therefor in the. outer cup-shaped socket 7, and hence preventing the electric current, which passes through the carbon disks, from flowing from t,hc bind ing-post- .to the. outer cup-shaped oeket". The. outer side of.,the soeket 7 ha"i' thereugrainsi. an insulatii g-plato n'evpnls ilmeurrent from Hoping from" the )llllllll; '-|)U. l to the socketf. A nut I53 turns on threads fUl'lllOLi'Ol] tlll ii1lllii-pust cane when turned in onedirectidn drawsrhe block fi-and insulating-cupfi lirmly-againsttl ebotmin-ofsnulwt'r', nm'l thereb v prevents entrance inl' air to the interioratthis end of the tube.

Within the tube 4 and surroundhdlwl' the insulating-tube Sure a series of Cnrlguilidis'lis l4, superimposedpne upon the other? I In the npplieationx-yfmy invention the rc- -sistanecdevice is arranged in an electrical circuit,. (not.shown,) one. wire to sand circuit being. umnu'eied lu he;bnnluw-post 9 and connection with the opposite end of the column of carbon latcs.

the binding-post, thence passes through the carbon plates, and thence out of the opposite end of the tube onto the wire electrically connected at that end. In order to regulate the degree of resistance, a com ression device (not shown) is employed, w ich acts on the carbon plates and compresses the same,

tially air-tight.

2 5'- R metallic tube 4, as clearly shown in the drawso as to effect a gradual cutting out of the resistance. This compression device does not, by preference, act directly on the carbon p ates, but upon a block 15, referably of metal and disposed in the end i posite to the end from which the bindingpost 9 rojects. This block fits closely to the wall 0 theinnerinsulati -tube 8, and therefore serves not only to ta e the direct thrust ofthe compression device, but also by its close fit effects a close enough joint at this end of the tube to render said end substan- In order to even more offectually make said end air-tight, the inner insulating-tube 8 ma be extended at said end a short distance beyond the end of the When this inner insulating-tube is composed of asbestos and is thus extended beyond the endof the outer tube, it will be found that it w'ill have a tendency to bend inwardl and its outer ed a will therefore approac said block more 0 ,osely. For the reason stated, therefore, I prefer to extend the inner insulatin -tube in the manner dedo not h to be understood as limiting myself th reto, inasmuc as successful'results may be obtaind where the inner tube terminates flush with the end or" the outer tube.

From the construction described it will-be seen that the opposite ends of the tube are rendered substantially air-proof by the provision of the inner insulatin -tube 8 in consection with the other parts 'sposed and arranged as described-:that is to say the insulatiu -tube 8, in connection with the block ran crs one end of the resistance medium substantially air tight andthe: insulatingh thecup-shaped ina min-t shaped socket render the opposite end 'of tube in connection wit sulating-socket 5, block 6, an

sait resistance 'de vice substantially air-tight, the insulating-bushing 11 and the also assisting in securing the air tig t joint.

Practice has-demonstrated that this pro-- visionof a substantially air tight tube for containing the carbon p ates makes-it possible to employ such carbon'platesin anfentirel. satisfactory manner in connectionwith an e ectric current controlling "device andwithout danger of the carbon'plates oxidizing or disinte rating at ordinary temperatures to.whioh tlie resistance mediumis subjected by the action of the electric current passing therethrough.

The current enters the tube over the tube opplate 12 'In Fig. 2 of the drawings I show a sli htly modified form of construction "vherein l employ a disk 16, preferably of carbon, which is next to and abuts against the block 15 and is of a substantial thickness, or, in other words, is of considerablv greater thickness than the other disks therebeneath. This piece of carbon permits the resistance medium to be sub'ected to a very high temperature without an or of corrosion, inasmuch as said disk ofl'ers ittle resistance to the current, and thereby becomes heated to a comparatively slight extent.

i The modified construction shown in Fig, 3 :admits ofa still higher temperature than the iform shown in Fig. 2 without danger of the carbon disks beconiingdisintegrated. This construction consis s in rendering the end of the tube where the pressure is exerted as completely air-tight as possible. Referring to this modification, the numeral 18 indicates an insulating-tubewhich surrounds the outwardly-extendingstem 17 of the block 15.

This tube 18 is surrounded by an outwardlyiextendin tubular projectionit) from a coupilingi20. he inwardly-extendingrim of this. ;coupling is intoriorly threaded and thesein- ;te'rior threads engage exterior threads formed.

fat the outer end of tube 4 whereby theh vided at its'outer and with an inwardlysextendin flange which when the nut is turned inwar y is rought firmly against the flan e ofthe tube 18, and consequentl securey clamps said flange to the outer on of the tubular rejection 39. From this construction it will be evidentthat a very close 'joint is provided against tho entrance of air. is close joint also effectually provides against thoentr'anceof dustinto the tube: 4'. In practice I have found that where dust or dirt entars the said tube and passes .to' the carbon T disks it ye seriously affects. the proper working oft a device I i What Lclaim as myinvention is- 11; The combination with a compressible "resistance medium of carbonaceous material in the form of lates, of a-contain'er inclosing the plates, am a gas-retaining-closin means therefor toprevent -oxii ,ation of sai plates 2.. The combination of a resistance medium of carbonaceous material in the form of'plates',i' a container inclo'sing the plates; ages-retainin'g closin' means't erefor to prevent oxidation of said plates, and'tneansJfOrsubjecting the latesto ressure to produce variable com uctivity ogthe-plates;= 2 3.1 Thecombination;- of "a yaridble-resist.

ance mdium of carbonaceous. material in the. form of plates, a container inelosing-th'e tainer, the closing means at one end being immovable and adapted to retain an air-excluding gas for preventing oxidation of the plates, and the-closing means at the other end being movable inwardly and outwardly in order to produce variable resistance of the plat-cs.

5. In a resistance device for electric-current controllers, the combination of an outer tubular casing, a resistance medium within the tubular casing, a coupling connected to one end of the tubular casing and having an outwardly-extending tubular pro'ection, a block within the tubular easing an adapted to bear against and compress the resistance medium, said block provided with an outwardly-extending stem, a tube within the outwardly-extending tubular projection of the coupling and surrounding the outwardlyextending stem of the block, and means for forming a substantiallyair-tight joint at the other end of the tubular casin j 6. In a resistance device or electric-current controllers, the combination of an outer tubular casing, a resistance medium withinthe tubular casing, a coupling connected to one end of the tubular casing and having an outwardl -extendiug tubular pro 'zction, a block wit in the tubular casingan adapted to bear against and compress the-resistance medium, said block provided with "an outwardly-extending stem, a tubewithin' the outwardly-extending tubular projection of .ie coupling and surrounding ;t'he'6utwardlyextending stem of the block, said tube having: a laterally-extending flange at its outer, end, a nut turning on threads-formed on the outwardly-extending tubular projection of the couplin and provided at its outer end with a latera inwardly-extending flange adapted to be brought against the flangeof t 1e tube which is surroundedby the tubular projection of the coupling, and means for forming a substantially air-tight joint at the other end of the tubular casing.

7. In a resistance device for electriecurrent controllers, the combination of a tube, a resistance medium within the tube, means forfo'rming a substantially airtight joint'at one of the ends of the tube, and two blocks placed together within the opposite end of the tube and closely fitting but movable in said end of the tube, the inner block bearin a ainst the resistance medium, and the sai( b ocks forming a substantially air-tight joint at said end of the tube.

8. In a resistance device for electric-eurrent controllers, the combination of an outer tubular easing, aresistauce medium within the tubular casing, a socket at one end of the tubular casing, a block in the bottom of the socket and upon which the resistance me dium bears, an outer socket inclosing the in- .ner socket and-connected to the outer tubular casing, a coupling connected to the other end of the tubular casing and having an outwardly-extending tubular pro'ection, a block within this end of the tubular .casing and adapted to bear against and compress the resistance medium, said block provided with an outwardlyextending stem, and a tube within the outwardly-extending tubular projection of the coupling, and surrounding 'the outwardly-extending stem of the block. i

9. The combination of a resistance medium of carbonaceous material, a container inclosing the carbonaceous material, ineans for forming a substantially air-tight joint at one of the ends of the container, and a block movable inwardly and outwardly in the opposite end of the container and a ainst the carbonaceous material at that cm of the container, the two opposite substantially air tight i joints of the container preventin oxidation of the carbonaceous material,yan said block adapted whenmoved inwardly toward the carbonaceous material to produce variable conductivity of said carbonaceous material.

10. The combination of a resistance medium,- a container'inclosing saidresistance medium, an insulating-tube in the container and surroundingthe resistance medium, a socket into which the inner insulating-tube extends, a block in the bottom of thesocket andclosely fitting the' upri ht wall of said socket, and'upon whichbloc -the resistance medium bears, an outer socketinclosing the inner socket and connected to the outer container, and-means for. form'ing'afsubstantially air-tight joint atthe opposite end of the container, the two op ositesubstantially air --ti ht joints of said containeripreventing oxi ation of the resistance medium;

In testimony whereof I ailix my signature inpresencc of twowvitnesses.

' LYNDE BRADLEY. Witnesses:

A. L. 'MoRsnLL, O. T. BENEDICT. 

